Why does my browser jump to a website I didn't want?

Your computer is infected with Malware, most likely.

Download and install Malwarebytes and run a full scan. This is one of the best anti-malware products available today and it's free.

Free - Malwarebytes - Good at removing malware, and acting as a back-up program and scanner.: http://download.cnet.com/Malwarebytes-Anti-Malware...

Yup, sounds like a bug..Malware bytes is a good one for free. Do you have an anti-Virus program too? If not, there's AVG free version or Avast anti-virus. Both decent, AVG may be a little easier to use...Just do a search and they will come up right away...There's also Advanced System Care free, that does everything to clean out your computer, although the free version doesn't update very often, so I use an extra anti-SPYware tool too. MalwareBytes should work fine as an alternate scanner even with ASC installed. If you encounter problems with any of these, just uninstall and try another one. There are several free security softwares out there, The ones recommended have a pretty good reputation....Good luck!

unless you have anti-virus, and firewall, like Norton's or McAfee,you have a hijacker on your computer.

You have a browser hijacker, use this:

http://www.superantispyware.com/

That'll get it.